Critical to the evaluation of potential therapeutics (pharmacological, gene, or cell therapies) are sensitive and repeatable physiological assessments of muscle function applied to mouse models of dystrophy. We have created a research core that performs cell culture, ex vivo, in situ, and whole animal assessments of muscle integrity and function. The main project proposed in this grant contain components that require muscle physiological measurements, as well as preliminary assessment of protein production in cultured myotubes. The Efficacy Assessment Core will meet the needs of the projects within this grant. In addition, the core will maintain colonies of mouse models of DMD and LGMD in order to support studies in which long-term testing is necessary. The resources of this core are contained within Dr. Sweeney's laboratory, which includes all instrumentation for muscle physiological measurements, as well as specialized equipment for cell culture, documented free wheel running, and treadmill running. Dr. Sweeney, the Core Director, is a muscle physiologist with extensive experience evaluating muscle function in mice. Dr. Huisheng Feng is an expert in muscle cell culture, Monica Zadel is an expert at performing muscle mechanical experiments, while Pedro Acosta maintains our breeding colonies and will monitor free wheel running experiments. Kevin Morine has extensive experience in Western blot analysis and quantitative PCR.